[Comparative study of antiviral activity of luteolin and 7,3'-disulfate luteolin].

Antiviral activity of 7,3'-disulfate luteolin, extracted from Zostera marina was studied on an experimental model of tick-borne encephalitis (TBE) in vivo and in vitro. The drug increased the survival of the experimental mice infected with TBE virus and prolonged their lifespan. It was shown that 7,3'-disulfate luteolin reduced the virus accumulation in the SPEV cells by 2.0-4.0 lg TCID50/ml.

[In vitro activity of luromarin against tick-borne encephalitis virus].

Luromarin, extracted from the sea alga Zostera asiatica, showed no cytotoxic activity when incubated with the SPEV cell culture and was characterized by virulicidal properties against highly pathogenic strain of TBE virus and the ability to inhibit the virus replication at the early stages of the infection.

[Viremia in patients with tick-borne encephalitis and in persons with attached ixodes ticks]. / Virusemiia u bol'nykh kleshchevym éntsefalitom i u lits s prisasyvaniem iksodovykh kleshchei.

An original method of virus isolation developed by the authors made it possible to collect 64 strains of tick-borne encephalitis (TBE) virus isolated from the blood of TBE patients and subjects complaining of sucking Ixodidae ticks. It is demonstrated that only a small part of the tick natural population cause acute TBE. The majority of the strains (54 isolates) of TBE virus have been isolated from the blood of clinically healthy subjects. Half of the strains showed no immunogenic properties in human body. Season infectivity corresponds to monthly virusophority of the ticks.

[Antigenemia in people infected with tick-borne encephalitis virus]. / Antigenemiia u liudei, infitsirovannykh virusom kleshchevogo éntsefalita.

An original modified method of tick-borne encephalitis (TBE) diagnosis was used to examine 1196 subjects. It is shown that tick bites frequently lead to TBE virus infection in all the age groups (24.9 +/- 1.3%). Antigenemia in febrile TBE form occurred in 45.8 +/- 6.0%, in severe form in 19.3 +/- 4.2% of cases. Children with the highest viremia and antigenemia are considered as an indicator system of TBE virus infection rate in the population in different seasons. Population of TBE virus consists of 2 parts. The prevalent part is inapparent and does not induce manifest infection. The other part of the virus population with similar seasonal activity gives rise to severe clinical forms of TBE with lethal outcomes.

[Effect of low-intensity radiation on the course of experimental tick-borne encephalitis]. / Vliianie nizkointensivnykh izluchenii na techenie éksperimental'nogo kleshchevogo éntsefalita.

Effects of low-intensive laser exposure in the 630 to 890 nm waveband on the course of experimental tick-borne encephalitis were studied in vitro and in vivo. Virus-static effect of the exposure was revealed: titers of the exposed virus dropped, infective activity decreased, and interferon production was inhibited. The exposure had no apparent effect on the virus which penetrated into the cells. In addition to its manifest prophylactic effect, low-intensive laser exposure is capable of activating the infectious process during the acute period of tick-borne encephalitis by causing more frequent and sooner death of animals. Effects of interferon inducers during the acute period of viral infections are discussed.

[Helium-neon laser radiation as an inducer of interferon formation]. / Geli-neonovoe lazernoe izluchenie kak induktor interferonoobrazovaniia.

Helium-neon laser has first been shown to be an active interferon inducer. Marked induction was found at various radiation power (1, 6-7, 20 MW) and at various radiation exposures: from 1 sec to 1 min both for single (up to 512 units/ml) and repeated (up to 1024 units/ml) effects on leukocytes of the donor blood. The major part of interferon was shown to be acid-labile and a lesser part was acid-stable alpha- and gamma-interferons. The above data are of both practical and theoretical importance for the elucidation of the pathogenetic mechanisms of positive therapeutic effect of this light on living beings.

[Molecular characteristics of tick-borne encephalitis virus from the Southern Sikhote-Alin endemic region]. / Molekuliarnaia kharakteristika populiatsii virusa kleshchevogo éntsefalita Iuzhno-Sikhoté-Alin'skogo ochagovogo regiona.

Molecular characteristics of 38 strains of tick-borne encephalitis (TBE) virus isolated in the Southern Sikhote-Alin focus were studied using 10 synthetic oligonucleotide probes complementary to the genomic RNA of the Sofyin strain. The isolated strains were divided into 4 groups, depending on the source of isolation: 1) strains isolated from Ixodes persulcatus (n = 8); 2) from the brain of patients dead from TBE (n = 10); 3) from the blood of patients with the febrile form of TBE (n = 7); and 4) from the blood of patients with an unapparent infection (n = 13). The total level of hybridization in the four groups was as follows: 61.8, 75.2, 55.8, and 35.2%. The "tick" strains with a great variety of the genofund are regarded as the stock group of the natural TBE virus population, 40% of which are strains close by their characteristics to avirulent strains of TBE virus.

[Pathogenetic criteria for evaluating the virulence of tick-borne encephalitis strains isolated in the southern part of the Far East]. / Patogeneticheskie kriterii otsenki virulentnosti shtammov virusa kleshchevogo éntsefalita, izolirovannykh na iuge dal'nego vostoka.

A comparative virological, immunological, and pathohistological study of 5 tick-borne encephalitis (TBE) strains differing by virulence was carried out in golden hamsters. The authors characterize the TBE virus pathogenicity sign, denoted as Pmaic genetic marker (pathogenicity for hamsters at intracerebral inoculation), which helps understand the essence of immunopathogenetic mechanisms of the TBE infectious process in man.

[A method of testing alpha-acid labile interferon and prospects for using it in disorders of interferon status]. / Sposob testirovaniia alpha-kislotolabil'nogo interferona i vozmozhnost' ego primenenii pri narushenikh interferonovogo statusa.

The authors discuss the possibility of using He-Ne laser for induction of alpha-acid-labile interferon. Use of this laser represents an additional test for the detection of diseases involving a deficient induction of alpha-acid-labile interferon.

[Apoptosis as a mechanism for the cytopathic action of tick-borne encephalitis virus]. / Apoptoz kak mehanizm tsitopaticheskogo deistviia virusa kleshchevogo éntsefalita.

The ability of tick-borne encephalitis (TBE) virus to cause programmed cell death (apoptosis) in viral infection of newborn mice and of two cell cultures is studied. The time course of virus antigen accumulation detected by enzyme immunoassay and of endonuclease fragmentation of nuclear DNA detected by agarose gel electrophoresis is compared. All three TBE strains differing by the source of isolation and biological characteristics can cause oligonucleosomal fragmentation of DNA of brain cells of two-day white mice and of SPEV cells in acute infection. In VERO-E6 cells the same three strains caused a latent infection; accumulation of virus antigen was not associated with endonuclease fragmentation of DNA or any other signs of cytopathic destruction. These data indicate that TBE virus can cause programmed cell death both in vitro and in vivo, which is apparently one mechanism of the cytopathic effect of the virus.